Bike riding can affect the reading. So can benign hypertrophy. So can infection. My PSA jumps up and down, all over the place. The urologist then tested something called "free PSA" and concluded there was no cancer. We did experiments in terms of riding the bike, not riding the bike, working the prostrate, not working the prostrate (to put it nicely), etc. Definintely makes sense to get more than one test (and to get the "free PSA" test) before going under a knife or getting the radiation.